I don't think it's that obvious Sapp is a HOFer. He had some good years but he was never the best player in the league in my opinion. He just ran his mouth and chased the cameras.
That's YOUR opinion. In actuality he helped to REDEFINE the Defensive Tackle position. There weren't many DT's posting sack numbers like Sapp and DISRUPTING OFFENSIVE LINES AS EFFECTIVELY until he came along. Sapp gave the DT position NEW LIFE. Even Kris Jenkins benefited from the possibilities.
True, Sapp is a loud mouth. But he is a HALL OF FAME-WORTHY LOUDMOUTH. Why is it that several teams run the Tampa 2 defense (even though the Bucs don't run it anymore)? Because Sapp was THAT effective in it.
It's not widely acknowledged outside of NFL circles, but Sapp was part of a LEGENDARY defense, in which he was a key cog that made it all work. Dungy BUILT A DEFENSE (that has been copycatted around the league) AROUND SAPP'S ABILITIES.
If that's not HOF worthy, then nothing is...